This invention relates to the harnessing of items, and, more particularly, to the precision harnessing of items and prevention of accidental release.
Harnessing devices are widely used for the bundling of objects. Such devices are typically formed by a serrated strap fitted to an apertured head containing an internal pawl that engages the serrations of the strap; or by an apertured strap fitted to a buckle-like head, with a tongue that enters the apertures of the strap. Examples are U.S. Pat. Nos. 3,106,028; 3,189,961; 3,457,598 and 3,590,442.
Harnessing devices with searrated straps have the disadvantage of being only as secure as their pawls. Attempts have been made to strengthen serrated strap devices but this has resulted in considerable complexity without achieving the desired end result. Similar objections apply to harnessing devices with buckle-like heads. In these devices, a tongue which enters the strap apertures rests against the head of the buckle near its opening and is deflected by the strap. The tongue is typically a cantilever attachment to the buckle-like head, which tends to be undly stiff in the direction of forward thrust during harnessing, and insufficiently stiff in the direction of reverse thrust applied by the strap because of the harnessed item.
An alternative type of harnessing device is of the kind shown in U.S. Pat. No. 3,766,608 which issued Oct. 23, 1973. This harnessing device is formed by a locking head with an attached ladder strap. The latter is advantageously of stretch-orientable material and is elongated by stretching. This has the effect of increasing the separation of the rungs of the ladder. As a result the strap does not permit minute or close pitch adjustments. The required length of the head and the adjustability of the strap are governed by the distance of separation between adjoining rungs, which can be considerable when the strap has been stretched.
Accordingly, it is an object of the invention to achieve the secure and precision harnessing of items. A related object is to achieve secure and precision harnessing without the need for employing complex structural configurations.
A further object of the invention is to overcome the disadvantages associated with ladder strap harnessing devices, particularly those with stretched straps, while simultaneously retaining their advantage. A related object is to achieve minute, or close pitch adjustments in stretched strap harnessing devices. Another related object is to reduce the required length of head in stretched strap harnessing devices.
Another object of the invention is to avoid accidental harness release. A related object is to enhance the security of the members that are used to engage the straps of harnessing devices.
Still another object of the invention is to provide ease of harnessing and resistance to spontaneous unharnessing. A related object is to provide a head configuration that facilitates cinching of a harnessing strap, but, at the same time, impedes the tendency of tightly cinched straps to pull away from their heads.
A still further object of the invention is to limit the tendency of pawls or tongues of harnessing devices to accumulate excessive stresses at their points of engagement with harnessing straps.
Yet another object of the invention is to achieve a locking head and pawl which is particularly suitable for use with stretched straps in which close pitch adjustments are attainable. A related object is to achieve a desirable locking pawl for ladder straps with closely spaced rungs that are contacted by one or more pawls of a locking head.